Process for making filter cups

ABSTRACT

A percolator having a cylindrical basket concentric with a wand is provided with a filter paper cup having an annular bottom coextensive with the bottom of the basket and having upstanding fluted sides. The filter cups are formed by cutting and forming them into a nest of cups having an imperforate bottom, transferring the nest of cups to a frusto-conical die having a circular top commensurate with the circular bottom of the filter cups, a central die-hole, and outwardly and downwardly flaring sides corresponding to the natural outward flare of the nested cups, and punching an axial hole in said nested cups while on said die by means of a punch complementary with said die-hole.

This is a division of application Ser. No. 686,109, filed May 13, 1976,now U.S. Pat. No. 4,098,177 issued July 4, 1978.

BACKGROUND OF THE INVENTION AND PRIOR ART

The invention relates to apparatus for making coffee and is particularlydirected to improvements in percolators for this purpose.

There are types of coffee makers now available in which the coffee isbrewed and filtered in an automatic or semiautomatic process. Still,many people believe that brewing coffee is an art rather than a scienceand prefer apparatus such as percolators where art rather than sciencegoes into the making of the coffee. It has been proposed, heretofore, touse filter cups of sorts in percolators but such as have been availablehave been expensive, inelegant, and relatively ineffective.

OBJECT OF THE INVENTION

It is an object of the invention to provide a new and improvedpercolator. It is a further object of the invention to providepercolators having disposable filters which are elegant, inexpensive andefficient. It is a further object of the invention to provide suchdisposable filter cups suitable for use in percolators. Still a furtherobject of the invention is to provide new and improved process formaking such filter cups. It is a further object of the invention toavoid the disadvantages of the prior art and to obtain such advantagesas will appear as the description proceeds.

BRIEF DESCRIPTION OF THE INVENTION

This invention relates to a new and improved percolator having acylindrical basket concentric with a tubular wand and a filter paper cuthaving an annular bottom coextensive with the bottom of said basket andhaving integral upstanding fluted sidewalls engaging the sidewall of thebasket and projecting upwardly from the periphery of said annularbottom; to a process for making the same in which a set of nested cupshaving a circular bottom and upstanding fluted sidewalls is first formedand then placed on a frusto-conical die having a circular topsubstantially the same diameter as the central portion of the nestedcups, a central die-hole, and sides flaring outwardly and downwardlycomplementary with the natural outward flare of the side walls of saidnested cups, and punching an axial hole in the bottoms of said nestedcups by means of a punch complementary to said die-hole; and to the cupsso formed.

In carrying out the process of the invention, a plurality of sheets orwebs of filter paper are assembled into a composite web and fed into anannular die having a peripheral cutting edge. The male and femaleportions of the die have radially extending complementary lands andgrooves whereby flutes are imparted to the annular portion of thecomposite disc in said die. The female portion of the die also has atubular extension having lands and grooves complementary to the landsand grooves in the male die portion. A ram having a diameter essentiallythe diameter of the cups to be formed then engages the fluted web offilter discs and forces it into said tubular portion, thereby forming anest of cups. The tubular portion has a tubular extension in which thenested cups are heated and cooled to ambient temperature. The heatingmay, advantageously, be effected at about 400° to 420° F. With eachoperation of the die, the nested cups are advanced in the tube adistance equal to the height or length of the nested cups andultimately, with each operation of the die, a set of nested cups will beejected from said tube. With each ejection of a set of nested cups, theset is transferred by hand or by suitable machinery to a frusto-conicaldie having a circular top substantially the same diameter as the centralportion of the nested cups, a central die-hole, and sides flaringoutwardly and downwardly complementary with the natural outward flare ofthe sidewalls of the nested cups. A punch complementary with said diethen punches an axial hole in the bottom of the set of nested cups.

The filter paper which has been found particularly useful for making thefilter cups of the invention consists essentially of pure bleachedcellulose fiber from chemically prepared wood pulp fibers. It isuncalendered and unsized, has a 28 to 40 pound basis weight, and a 16 to15 percent crepe. Other types may be used, however.

The nested cups thus produced have an annular bottom and upstandingsidewalls having accordion pleat-type flutes therein with rectilinearapices and are adapted for insertion into the basket of percolator. Forthis purpose it is of advantage to have a large number of flutes,preferably 1 flute at least every 10 degrees and, at most, not more than1 every 15 degrees.

These cups are particularly adapted for use in percolators in which thebasket has an axially disposed, tubular collar which projects upwardlyfrom the bottom of the basket and embraces the wand with a sliding fitso that the basket can be removed from the wand. The annular bottom ofthe filter cup is coextensive with the annular bottom of the basket andextends from the axial collar to the sidewall of the basket. It will beunderstood, however, that in the broader aspects of the invention, thecups may be designed for use in a percolator in which the basket and thewand are integral, in which case, the axial aperture in the filter cupwill have the same diameter as the wand.

The process of the invention is particularly adapted to producing cupshaving an accurately centered aperture so that when the cups are placedin the basket of the percolator, the annular bottom of the filter cupwill be coextensive with the bottom of the basket and the outermostapices of the flutes of the filter cups will be in uniform engagementwith the sidewall of the basket.

DETAILED DESCRIPTION OF THE INVENTION

In the Drawings:

FIG. 1 is a schematic view in side elevation showing how the nested cupsare formed.

FIG. 2 is a plan view of a filter cup according to the invention.

FIG. 3 is a side view of the same cup.

FIG. 4 is a detailed view of the cup-forming die and the heating andcooling tube.

FIG. 5 is a plan view of the punching die assembly.

FIG. 6 is a cross-section taken along line 6--6 of FIG. 5.

FIG. 7 is a side elevation in section of a percolator basket and wandhaving a filter cup therein.

FIG. 8 is a cross-section of the basket of FIG. 7.

Referring now, particularly to FIG. 1, a plurality of single sheets orwebs 10 of filter paper are assembled as illustrated into a compositeweb 12, which is fed by suitable roller means 14, 16, 18, and 20 intothe forming die 22 operated by the ram press 24, where the composite web12 is cut and shaped into nested cups 26, which pass through the heatingtube 28 and the cooling tube 30.

The roller 18 is constructed and arranged to take up the slack in thecomposite web during the forming operation, in which case the roller 14operates continuously. Alternatively, the roller 12 may be operatedintermittently to feed the composite web to the forming die 22 asneeded.

The forming die 22 is provided with an annular cutting ring 32 operatingon the annular anvil 34 and is provided with a female portion 36 and amale portion 38, which latter is operated to and from the position shownin dotted lines by the ram press 24. The female portion 36 of the die 22is provided with alternating lands 40 and grooves 42 and the maleportion is provided with complementary lands and grooves 44 and 46adapted to form flutes in the annular portion of the cut filter discswhich are clamped between the annular portions of the female and maledie portions 36 and 38.

The female portion 36 of the forming die 22 has a tubular extension 48and the lands and grooves 40 and 42 extend into this tubular extensionas shown by the dotted lines up to the shoulder 50, where the tubularextension 48 is enlarged to receive the heating and cooling tube 52which is composed of heating section 28 and cooling section 30.

The heating section 28 is provided with one or more heating elements 54which may be continuous or spaced about its length as shown in FIG. 4,and the whole is lapped with insulating material 56 which may beasbestos, polyurethane foam, or any other suitable insulating material.

The female die 36 with its tubular projection 48 is sweated into orotherwise fastened to a collar 58 which is fastened to the ram press 24by tie rods 60. The male die member is affixed to the ram 62 of the rampress 24.

The ram 62 is hollow, having a diameter roughly corresponding to that ofthe forming die. Disposed axially in the hollow ram is a pusher 64, thefront end 66 of which has a diameter roughly corresponding to the insidediameter of the nested cups. Advantageously, the pusher 64 may slopeoutwardly as shown at 68 at an angle of between about 1 and 5 degreesand, if desired, may be fluted to provide alternating lands 70 andgrooves 72 corresponding, respectively, to the grooves 42 and lands 40of the female die 36 and its tubular extension 48. The pusher 64 isaffixed to the end of rod 74 which can be actuated by means, not shown,in the ram press 24 to push the composite web out of the die after ithas been cut and formed therein and into the tubular extension 48. Afterrepeated operation as above described, the heating and cooling tube 52will be filled with a plurality of columnarized nested cups 26. Finally,after the requisite number of operations, one set of nested cups 26 willbe ejected from the heating and cooling tube 52 as shown in FIG. 1.

The set of nested cups thus ejected is then transferred either by handor by mechanical means to a die where a center hole is punched in thebottom of the cup.

FIG. 5 shows in fragmentary form a suitable die machine for thispurpose, including a turntable 76 adapted to be rotated by indexingmeans, not shown, from loading station A to punching station B todischarge or unloading station C. A fourth station, D, is shown whichmay be utilized for unloading or for loading as desired, or may beomitted entirely.

Each station is provided with a punch die 78. Each punching die 78 isprovided with a base 80 having an annular flange 82 at the bottomthereof. The base 80 is secured to the turntable 76 by means offasteners 84 in the flanges 82.

The base of the die 80 is shaped like a truncated cone, the top surfaceof which has essentially the same diameter as the bottom of the filtercups and the sides of which slope outwardly and downwardly as shown at88 substantially at the angle of flare of the nested cups after they aredischarged from the cooling tube. Ordinarily, it will be sufficient ifthe sides slope outwardly and downwardly at an angle of about 10 toabout 30 degrees.

The top of the die base 80 has an axial die-hole 90, axially alignedwith punch 92. When the nested cups 26 are placed on the die base 80, asshown in FIG. 6, the cups are automatically centered so that the punch92 will punch a hole in the bottom of the nested cups which is at theexact center of the several cups in the nest. If desired, a clamp, notshown, may be arranged to press the nested cups firmly in contact withthe top 86 of the die base 80 before the punching operation.

The individual cups are proportioned to conform with the basket 94 of astandard percolator, not shown. The basket in the form shown in FIG. 7has an upstanding sidewall 96 and a bottom 98. The bottom is perforatedand, if desired, part or all of the sidewall 96 may be perforated.Extending axially upwardly through the basket 94 is a wand 100. In theform shown, the basket 94 has an axial collar 102 projecting upwardlyfrom the bottom 98 of the basket. The wand 100 has a slidable fit withthe collar 102 so that the basket can be removed from the wand andreplaced as desired. In some forms of percolators, the basket rests onspring 104 which is affixed to the wand 100 at some lower point 106. Inother forms, not shown, the collar 102 is omitted and the bottom 98 ofthe basket is attached to the wand.

The filter cup 26a produced by the process of the invention is shown inFIGS. 2 and 3. It has an annular bottom 108 with an axial opening 110 ofthe same diameter as the collar 102, and upstanding sidewalls 112. Theupstanding sidewalls 112 are provided with a plurality of flutes 114about the periphery thereof which function, as shown in FIGS. 7, and 8like accordion pleats when the filter cup is placed in the basket of thepercolator, thus acting to take up the surplus paper and allowing thecup to assume roughly the cylindrical shape of the basket of thepercolator, with the outermost apices of the flutes being substantiallyentirely in contiguous relationship with the inner wall of the basket ofthe percolator.

In order for the filter cup to effectively assume the cylindrical shapeof the basket of the percolator, it is advantageous that the center holebe accurately centered and the flutes be relatively small. Preferably,there should be at least 1 flute for every 10 degrees of the peripheryof the annular base of the filter cup and, advantageously, 1 flute forat least every 15 degrees. Advantageously, also, the filter paper iscomposed essentially of bleached cellulose fiber from chemicallyprepared wood pulp which is uncalendered and unsized, is creped about 6to about 15 percent, has a moisture content between about 3 and about 6percent, and has about 28 to about 40 pound basis weight. When thefilter cups are so constructed and the flutes are heat-set by adequateheating in the heating tube, and adequate cooling in the cooling tube, afilter cup is provided which is inexpensive to make, elegant inappearance, and efficient for its intended purpose.

The cooling tube 30, advantageously, is perforated as shown at 116 and,if desired, the perforations may extend up into the portion of theheating tube 28 which is covered by the heating element 54b.

The female member 36 of the forming die 22 is dish-shaped or concave,whereas the male portion 38 is convex. This facilitates the pulling outof the annular fluted portions from the die when the pusher 64 engagesthe central portion of the cut and formed composite web to push it intothe tubular extension 48. Thus, the annular portion of the female member36 slopes upwardly as shown in FIG. 4 and the annular portion of themale member 38 has a complementary slope. The angle of slope ordinarilyis around 10 to 15 degrees, but, if desired, may range from an angle ofabout 10 to about 30 degrees.

The length of the heating tube 28 and the length of the cooling tube 30is not critical and may be varied over a wide range consistent with thepurpose of obtaining a good set of the flutes in the filter cup.

It is to be understood that the invention is not to be limited to theexact details of the operation or structure shown and described asobvious modifications and equivalents will be apparent to one skilled inthe art.

We claim:
 1. A process for making filter cups having an annular bottomand integral upstanding fluted sides projecting upwardly from theperiphery of said annular bottom which comprises(1) assembling into acomposite web, a plurality of webs of filter paper composed essentiallyof bleached cellulose fiber from chemically processed wood pulp, whichis uncalendered, is unsized, is creped from about 6 to about 15 percent,and has a basis weight between about 28 and about 40 pounds. (2) passingthe composite web into a die which cuts the composite web into acircular composite disc and forms flutes therein radiating out from acentral circuit portion, (3) forcing the fluted circular component discinto nested cups and moving the nested cups axially through acylindrical tube having substantially the diameter of the centralportion of the nested cups, (4) heating and cooling the nested cupswhile in said tube, (5) transferring the cooled nested cups from saidtube to a frusto-conical die having a circular top having substantiallythe same diameter as the central portion of the nested cups and acentral die-hole, said die having sides flaring outwardly and downwardlyfrom said circular top at an angle approximating the natural flare ofthe nested cups, and (6) punching an axial hole in said nested cupswhile on said die by means of a punch complementary to said die.
 2. Theprocess of claim 1, in which the sides of the die flare outwardly anddownwardly at an angle of between about 10 and 30 degrees.
 3. Theprocess of claim 1, in which the cutting and fluting die hascomplementary pairs of fluting lands and grooves at least every 15degrees.
 4. The process of claim 1, in which the cutting and fluting diehas complementary pairs of fluting lands and grooves at least every 10degrees.
 5. A process for making filter cups having an annular bottomand integral upstanding fluted sides projecting upwardly from theperiphery of said annular bottom which comprises(1) assembling into acomposite web, a plurality of webs of filter paper composed essentiallyof bleached cellulose fiber from chemically processed wood pulp, whichis uncalendered, is unsized, is creped from about 6 to about 15 percent,and has a basis weight between about 28 and about 40 pounds, (2) passingthe composite web into a die which cuts the composite web into circularcomposite discs and forms flutes therein radiating out from a centralcircular portion, (3) forcing the fluted circular component discs intonested cups and moving the nested cups axially through a cylindricaltube having substantially the diameter of the central portion of thenested cups, (4) heating the nested cups while confined in said tube inan elongate front section thereof, (5) cooling the heated nested cupswhile confined in said tube in an elongate end section thereof, byexposure to the ambient atmosphere through perforations therein, and (6)punching an axial hole in said nested cups.
 6. The process of claim 5,which further comprises transferring the cold nested cups from saidperforate section to a frusto-conical die having a circular top havingsubstantially the same diameter as the central portion of the nestedcups and a central die-hole, said die having sides flaring outwardly anddownwardly from said circular top at an angle approximating the naturalflare of the nested cups, and there punching said axial hole in saidnested cups while on said die by means of a punch complementary to saiddie.
 7. The process of claim 5, in which the heating is effected byexposure to a heating means while said nested cups are confined in animperforate section of said tube.
 8. The process of claim 7, whichfurther comprises transferring the cold nested cups from said perforatesection to a frusto-conical die having a circular top havingsubstantially the same diameter as the central portion of the nestedcups and a central die-hole, said die having sides flaring outwardly anddownwardly from said circular top at an angle approximating the naturalflare of the nested cups, and there punching said axial hole in saidnested cups while on said die by means of a punch complementary to saiddie.
 9. The process of claim 5, in which the sides of the punch dieflare outwardly and downwardly at an angle of between about 10 and 30degrees.
 10. The process of claim 5, in which the cutting and flutingdie has complementary pairs of fluting lands and grooves at least every15 degrees.
 11. The process of claim 5, in which the cutting and flutingdie has complementary pairs of fluting lands and grooves at least every10 degrees.
 12. The process of claim 9, in which the sides of the punchdie flare outwardly and downwardly at an angle of between about 10 and30 degrees.
 13. The process of claim 8, in which the cutting and flutingdie has complementary pairs of fluting lands and grooves at least every15 degrees.
 14. The process of claim 8, in which the cutting and flutingdie has complementary pairs of fluting lands and grooves at least every10 degrees.